Cylinder pressure sensors are known that are integrated as much as possible into an already-existing component of the internal combustion engine. Typical embodiments are the integration of a suitable pressure transducer into a spark plug, a high-pressure injection valve, or a glow plug. The pressure transducer is usually clearly separated from the combustion chamber; on the one hand, the front part of the component is already allocated to the main task of the component and does not offer any constructive space for the pressure transducer, while on the other hand the pressure transducers are frequently provided with integrated electronic circuits that cannot be exposed to the high temperatures near the combustion chamber. The cylinder pressure is then transmitted from the combustion chamber to the pressure transducer via suitable ducts in the component.
It is known that these ducts can cause significant falsifications of the cylinder pressure signal. They act as resonators, and what are known as whistle oscillations falsify the signal. FIG. 2 shows a pressure curve with superposed whistle oscillation. A detailed analysis of the cylinder pressure and the calculation of suitable features is thus no longer possible. High-quality cylinder pressure sensors avoid this falsification by housing the pressure transducer flush with the combustion chamber.
An object of the present invention is therefore to enable more precise measurement of the temporal pressure curve even without housing the pressure transducer flush with the combustion chamber, and to suppress interference portions resulting from whistle oscillations.